Simpson Cleaning MSH3125-S Gas Pressure Washer Review

By Power Tools

September 10, 2020


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Features and Specifications

  • Easy to start Honda GC190 engine.
  • Durable and flexible high-pressure hose. 
  • Anti-corrosion welded steel frame.
  • Pneumatic tires for easy movement. 
  • 5 nozzle tips for a variety of cleaning options. 
  • 3200 PSI
  • OEM Technologies™ axial cam pump.

This machine is a happy medium with the power of commercial power washing tools and the price of a garden tool. The MSH3125 - S has a host of great features that will make cleaning the patio, furniture, or sidings a breeze. 


The MSH3125-S features a Honda GC190 engine which has a fair amount of power for its small size. The engine has no problem powering the pump and you won’t feel any loss of power or pressure when using the machine. 

The ripcord is strong and sturdy and should get the engine chugging over on the first or second pull. You won’t get too much resistance from it which should save your neck and shoulders a bit of ache. 

The small size of the engine reduces the overall weight of the machine for which you will be grateful when moving it around your yard. Overall this is one of the lighter gas-powered jet washers you’ll find. 

Honda is well known and liked for its reliable small engines. You can put your trust into this sturdy little engine. The oil needed for engine lubrication is usually supplied with the machine which is a bonus and filling the oil is really easy. 

Some users have reported oil leakages during shipping where the oil has been poorly protected during posting. This is obviously less than ideal and will be a real pain to remove. There does seem to be a trend of poor customer service from Simpson and this oil issue seems to be a symptom of this. 


This unit includes an OEM Technologies axial cam pump that connects horizontally to the engine. This is quite unusual for gas-powered pressure washers as the usual configuration is vertically stacked configuration. The horizontal layout makes it much easier to access the pump and attach the hose. It also makes the whole unit much more stable. 

The axial pump also benefits from a brass pump head rather than an aluminum pump head which is much more durable as the threading won’t wear down as quickly as brass is stronger and also doesn’t oxidize. 

The only downside to these axial pumps is that as they are direct drive pumps, they spin at the same speed as the engine. This will make the pump wear down more quickly than other types of pumps. 

On the other hand, axial pumps are more economical as they have fewer parts and need almost no maintenance. They are also much cheaper than triplex pumps for example. This is why the MSH3125 - S pump has such a great price. 

The PSI of the machine is 3200 thanks to this little beast of a pump. It will be more than enough pressure to clean all aspects of the home and garden. You may need to choose a different nozzle and stand further away if you want to clean the car. At 3200 PSI it is far too powerful to use as-is on a car without stripping the paint. 

Hose and Nozzles 

The hose on this pressure washer is advertised as a ¼ inch Morflex hose. This technology is abrasion-resistant, flexible, and non-marring. With 25ft of length, it’s not the longest hose out there but it is enough for most gardens.

The hose attaches to the pump at the back. The hook up is really accessible so no bending and crouching to try and attach the hose. As mentioned, the hose has a brass coupling like the pump head so it is durable and resistant to stripping. Many users find the brass coupling to be excellent and a bit of a surprise at this price range to be honest. 

Five nozzles are supplies with the washer and are easily and conveniently stored on the handle. They are 0°, 15°, 25°, 45°, and a soap dispenser.  Some users do say that the nozzles can vibrate out of their holder when the washer is working. It’s not a big complaint but it does feel a bit of a silly design flaw. 

The narrower nozzles provide lots of pressure which is perfect for stubborn stains and moss. The 15° nozzle is a favorite with many owners as it seems to offer enough pressure and surface area to clean paths and driveways efficiently. 

The 20° and 40° nozzles dissipate the pressure low enough to wash a car with, though as previously mentioned you should still consider standing further back to make sure you don’t chip your paint. 

The soap nozzle works with a downstream injection system. You need to attach the soap hose to the hose barb and stick the filter in your chosen detergent or cleaner before spraying through the black low-pressure soap nozzle. This does seem to work well enough but it’s not the slickest setup. 

The spray wand is sturdy enough although the plastic handle could be slightly more durable. There are some issues with the handle cracking under prolonged use. 

Wheels and Construction

The pneumatic wheels are super handy. Even though the unit is fairly lightweight compared to other washers, you would struggle to move it around easily without the wheels. These tires make dragging the unit around simple even over curbs and bumps. 

They seem to be very sturdy and aren’t likey to puncture or break anytime soon. The axel they sit on is a common ⅝ “ axel so if you do ever need to replace them, you will be able to find replacements easily. 

The overall construction of the washer is simple and sturdy. The welded steel frame provides a balanced and secure base for the pump and motor. The layout of the frame also offers a little bit of protection for the motor and pump from falling debris or other similar things. 

Set up is a breeze and requires no tools. The handle attaches with knob handled screws and is easy to get in place. One thing to note is that the handle is shorter than other models. This is because the horizontal layout doesn’t require it to be so tall. The height, or lack thereof, isn’t too uncomfortable though most users recommend pulling rather than pushing. 

Cleaning Performance

With the combination of quality pump, engine, and hose, this washer has incredible cleaning power. It cuts through grime, dust, and moss growth with no issues. Harder stains like tipped paint can be removed using the narrower nozzles. 

This machine is perfect to prepare surfaces for further treatment like painting or varnishing as it gets rid of all the dirt and grime in seconds. It can cut through years of muck and paint easily and efficiently.

The engine comes with a 2-year limited warranty and the pump has a 1-year limited warranty. This offers you a bit of safety if you have any issues. However, the major complaint amongst users is that Simpson’s customer service leaves a lot to be desired. They have a customer service line you can call but the quality of the service provided over those calls is patchy at best. 


  • The Honda GC190 engine is reliable and easy to start.
  • The smaller, lighter engine is quieter and easier to maneuver.  
  • OEM Technologies’ axial cam pump gives excellent pressure. 
  • The bronze pump head is durable and easy to access. 
  • The horizontal layout is more stable and easy to access. 
  • Selection of nozzles for all cleaning jobs.
  • Pneumatic wheels are great for moving the unit. 
  • Strong cleaning performance removes dirt, grime, paint, and plant growth. 


  • Poor customer service.
  • Axial pumps have a shorter life span. 
  • Some report poor shipping which results in oil leaks.
  • The wand handle could be more sturdy. 
  • Nozzles sometimes slip out of their holders. 


The Megashot MSH3125  - S is a great bit of kit that toes the line between commercial and professional power washers. The engine, pump, and construction are high-quality and dependable. 

The power of this machine is perfect for all home and garden cleaning jobs and will serve you for several years if you take care of it. The first thing to go would be the axial pump but luckily these are easily replaceable so you can theoretically extend the life with a simple exchange. 

We don’t see any major flaws with this washer, little niggles like the shortish length hose and the nozzles vibrating out of their holders are more frustrating than critical failures. 

Our only concern is the level of customer service provided by Simpson. The best-case scenario is that you never need to contact customer service, but if you are unlucky enough to need to replace missing or broken parts we can’t promise that you will have a satisfactory service.